The present invention relates to a method of increasing the robustness of microcomponents formed of silicon. In particular, the present invention relates to coating the microcomponents with a ductile metal to increase their robustness.
Many micro-electro-mechanical systems (MEMS) devices and other microcomponents are formed of silicon or other brittle materials. Though extremely brittle, silicon has become the industry standard for several reasons. First off, because of modem etching techniques, it is possible to form very precise microcomponents by etching them from silicon. As a result, much of the equipment and processing in many microcomponents facilities are configured for working with silicon.
In addition, the MEMS industry is influenced by and follows the semiconductor industry. The semiconductor industry has used silicon in making its components, and as a result, has perfected techniques for working with silicon. Furthermore, if the MEMS device has electrical connections or is to be integrated into other electrical components, it is preferable that the MEMS device be made of silicon.
Though silicon is a relatively strong material, it is also very brittle. When handling a MEMS device made of silicon, the MEMS device will typically come into contact with such traditional tools as tweezers, robot pick and place tools, and pin contacts. Any time the silicon MEMS device is contacted by one of these tools, stress concentrations at the location of contact may be created. These locations are very susceptible to chipping, cracking, or even breaking due to the increased stress concentrations.
When a silicon component is chipped during handling, the small amounts of silicon which chip off may contaminate nearby electrical components. Should the silicon device crack during handling, there is an increased likelihood that the entire device will break. This is because MEMS devices are often formed of a single silicon crystal. Once the single crystal is cracked, the crack may easily develop into a major break. Contamination can also result from cracks and breaks. Further, should the silicon MEMS device crack, chip, or break, the device may no longer be useful.
Therefore, there is a need in the art to form silicon microcomponents and MEMS devices in such a way that their robustness can be increased so that there is less breakage and less contamination caused due to chipping, cracking, or breaking.
The present invention is a silicon microcomponents or MEMS device which is coated with a ductile metal at a contact interface. The silicon microcomponents or MEMS devices having this armored coating are much more robust, less prone to breakage, and less likely to chip. The armored coating of the MEMS device may comprise either partial armored coating or total armored coating. Total armored coating comprises coating the entire device with the metal, while partial armored coating involves coating the MEMS device with metal at only desired locations, such as the locations which will be contacted most often by a tooling mechanism.